<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta http-equiv="X-UA-Compatible" content="IE=edge" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>Document</title>
    <style>
      body {
        margin: 0;
        padding: 0;
        box-sizing: border-box;
      }
      .box {
        display: flex;
        background-color: saddlebrown;
        height: 100vh;
        /* align-items: center; */
        /* justify-content: center; */
      }
      .son {
        width: 200px;
        height: 200px;
        background-color: rebeccapurple;
        margin: auto;
      }
    </style>
  </head>
  <body>
    <div class="box">
      <div class="son"></div>
    </div>
  </body>
</html>
